Wood preservative



. taining only amino groups aminophenols, water-solub e salts,

Patented Apr. 14, 1931 sra'rss KARL HEINRICH WOL'MAN', OFBERPIhl-GBUNEWALD, AND HANS PFLUG, OF BERLIN- STEGLITZ, GERMANY,ASSIGNORS T GE'UBENEQLZ-IlliPRfi-GNIERUNG, G. M. B. 5., 0E

e 5. R'LOTTENBUBG, GERMANY WO0D ZFRESEEVATIVE Ito Drawing.

certain disadvantages. The copper sulphate 1 cidal action and cannot beemployed in iron impregnating vessels. Zinc chloride, also. is notsufiicientl efiective; furthermore it 18 too easil was ed out of thewood by atmospheric eposits and it attacks the iron armourin s of thewood, forming h drochloric acid. itrated phenols or salts t ereof havethe drawback that they are more or less ex plosive and that theiraqueous solutions decom ose and corrode the iron of the vessels in w ichthe wood is impregnated.

The present invention enables these drawbacks to be avoided. Theinvention consists in employin amino-phenol salts or those acids whichgiemselves have a fungicidal action. For instance use may be made or thewater-soluble I hydrofluoric acid, fluos1l1c1c acid, arsenious acid andarsenic acid salts of amino derivatives of henols, cresols, xylenols orna hthols. he invention is not limited to t e use of particular acids orparticular aminophenols, but all suitable acids and aminophenols, i. e.,for instance mono, di-, or polyaminophenols, may be used. lhe

said salts of amino henols are not explosive and are very big yeffective, so that even when used in a small quantity, they afford athorou h and permanent protection-to the wood. nstead of phenolderivatives conuse may also made of those aminopheno which, in additionto the amino groups, contain one or more nitro grou s. It has alsoproved advisable to add to t e salts of amino henols 01f mtroor inlsolutions has an insufliciently strong fungi Application filed August25, 1927. Serial Ho. 215,529.

stance alkali salts, of those acids which are used to form salts withthe aminophenols. For instance, sodium fluoride may be added tothefluorides of aminophenols, or potassium arsenite to the arsenites ofamino= phenols, and so on. These additions increase the stability of thesolutions and also help to protect the wood by their own fungicidalaction. Mixtures of several amino henols, and also mixtures of severalof the a ditions referred to, may also be employed. It is also possibleto add to the described preservatives other compounds which have apreserving actihn or which reduce the inflammabilit of the wood andfinally also compounds w i ch protect the iron from corrosion.

The solutions of the new Wood preservative maybe used in any suitablemanner for impregnating the wood. The latter may be coated with thesolutions or steeped in the solution in open receptacles or, as is mostadvisable, the solution may be introduced into the wood in closed ironvessels with the employment of vacuum and pressure.

For example, 1 kg. of arsenite of paraaminophenol, which is obtained byboiling aminophenol with an excess of aqueous arsenic acid and allowingthe resulting compound to crystallizeout, is dissolved in 100 kg. ofwater and this solution isused for coating or impregnating wood.

Alternatively 9.4 kg. of the fluoride of 2,4-nitroaminophenol' isdissolved in 100 kg. water and the wood is treated with this solution,for instance by coating. The fluoride of 2,4-nitroaminophenol isobtained by dissolving 2,4-nitroaminophenol in an excess of aqueoushydrofluoric acid, evaporating the solution, dissolving the residue inhot Water and allowing the solutionto crystallize.

As a further example, 0.2 kg. of the fluoride of 2,4-nitroamino'phenoland 1 kg. of sodium fluoride may be dissolved in 100 kg. water andthewood treated with this solution in 00' closed vessels, a vacuum andpressure .being em ed.

{ hat we claim is 1. A wood preservative, consisting of alka] fluoridesand compounds of nitroaminophenols with hydrofluoric acid. a

2. A. woo'd preservative, consisting of sodium fluoride and compounds ofnitro-' v aminophenols with hydrofluoric acid.-

In testimony whereof we have signed our names to this specification.

KARL HEINRICH WDLMAN.

DR. HANS PFLUG.

